Function servings(size, shape)
If shape = "Round" Then
    servings = RoundPlate(size)
ElseIf shape = "Square" Then
    servings = SquarePlate(size)
Else: servings = 0
End If
End Function

Function RoundPlate(size)
  If size = "5 inch" Then
    RoundPlate = 6
ElseIf size = "6 inch" Then
    RoundPlate = 8
ElseIf size = "7 inch" Then
    RoundPlate = 10
End If
End Function